Engine crankcase breather valve



1966 H. H. WAGNER 3,265,084

ENGINE CRANKCASE BREATHER VALVE Filed 0012. 14, 1964 ELE INVENTOR.HAROLD H. WAGNER BY MW/ United States Patent "ice 3,265,084 ENGINECRANKCASE BREATHER VALVE Harold H. Wagner, Peoria, 111., assignor toCaterpillar Tractor Co., Peoria, 111., a corporation of California FiledOct. 14, 1964, Ser. No. 403,821 3 Claims. (Cl. 137-508) This inventionrelates to internal combustion engines and particularly to engineshaving means to communicate vapors or gases under pressure in an enginecrankcase to the intake manifold or other part of the air inductionsystem of the engine.

The commonly known engine crankcase vent to relieve pressure from anengine crankcase which results from blow by or leakage of pressure fromthe combustion chambers past the piston rings, as well as from othercauses, has been recognized as a contributing factor in the pollution ofair in cities and other densely populated areas. One means that has beenemployed to prevent air contamination by internal combustion enginesincludes a conduit connecting the crankcase with the intake manifold sothat pressure in the crankcase forces gases therein, which are usuallyof a combustible nature, into the engine intake where they are consumedwith the engine fuel. It is recognized that occasional pressure at theintake side of the engine, as may be caused by back firing at thecarburetor, is communicated to the crankcase through such a conduit andcan cause a dangerous explosion. It is also known that excessive vacuumat the intake side of the engine can cause withdrawal of lubricating oilfrom a crankcase.

Various check valves and the like have been devised in attempts toovercome the above mentioned disadvantages but moving metal parts ofsuch devices are subject to becoming gummed and inoperative in theenvironment of heavy oil vapors to which they are subjected.

It is, therefore, an object of the present invention to provide a valvefor the purpose described which is simple, trouble free, positive inoperation and economical to manufacture and which will open underpressure from the engine crankcase but will be closed by pressure fromthe opposite side and will also be closed by excessive low pressure orsuction from the opposite side.

Further and more specific objects and advantages of the invention aremade apparent in the following specification wherein the invention isdescribed in detail by reference to the accompanying drawing.

In the drawing:

FIG. 1 is a schematic view in front elevation of an internal combustionengine showing a conduit connecting the crankcase to the engine airintake and a valve enibodying the present invention in said conduit; and

FIG. 2 is an enlarged sectional view through a valve embodying apreferred form of the present invention.

In FIG. 1, an engine 1% is illustrated as having a conduit 11communicating between its crankcase and a conduit 12 which leads to theengine intake manifold. A valve, generally indicated at 14- and shown indetail in FIG. 2, serves to admit gaseous fluid under pressure from thecrankcase to the intake manifold while at the same time preventingreverse flow in the event of a pressure condition existing in the intakemanifold and also preventing fiow in the normal direction, that isbetween the crankcase and the manifold, which might be induced bysuction in the manifold.

Referring now to FIG. 2, the valve is shown as having a body memberformed of two parts 15 and 16 joined in any suitable manner, hereillustrated as a sliding connection secured by a snap ring 17. The part15 has an inlet opening 13 which is connected with the engine crankcasein use and the part 16 has an outlet opening 19 to be connected with theintake side of the engine.

3,255fi8d Patented August 9, 1966 The interior of the valve body isdivided by a diaphragm 20 of flexible rubber-like material which isresistant to the destructive effect of hydrocarbons. This diaphragm hasa central opening, the margin of which seats against a valve seat 21 inthe valve part 15 and has a central tube-like extension embracing aninwardly extending nipple 22 which communicates with the outlet 19. Thediaphragm may be held in place by any suitable means but is here shownas clamped at its outer marginal edge by an annular projection 23 on thevalve part 16 and as elastically embracing the nipple 22. The generallytubular part of the diaphragm which extends between the inner marginengaging the valve seat 21 and the nipple 2 is formed as a bellowshaving at least one outwardly extending fold illustrated at 24.

In operation pressure to be relieved in the crankcase is exerted againstthe fiat portion of the diaphragm 20 collapsing the bellows-like part sothat it moves away from the seal 21 and permits the gas to flow past theseat and outwardly through the outlet 19. In the event of unusually highvacuum or suction in the inlet side of the engine which might effectwithdrawal of oil in liquid form from the crankcase, the valve istightly closed because it tends to collapse the bellows or fold 24inwardly which also tends to lengthen it in an axial direction and causepressure against the seat 21. The same construction acts to preventpressure as from back firing at the suction side of the engine fromblowing back into the crankcase with an attendant hazard of explosionand fire. Any such pressure entering the valve through the outlet 19acts against the inner surface of fold 24 in that area closest to thevalve seat 21 as indicated at 26. Pressure in this area obviously alsourges the diaphragm toward a closed position against the seat 21. Freeflexing of the diaphragm and of the bellows portion thereof isfacilitated by an opening 27 which vents the otherwise closed areabetween the diaphragm and the valve part 16.

The valve of the present invention is inexpensive to manufacture, doesnot clog and requires no adjustment. Furthermore it serves to maintain alow positive pressure in the engine crankcase to prevent the entry ofdirt which results from pressures below atmospheric.

What is claimed is:

1. A valve to control fluid flow comprising a housing having inlet andoutlet passages, a centrally dis-posed valve seat, a valve elementnormally closing connection between said passages, means to permitopening of the valve by pressure in the inlet passage, said valveelement comprising a diaphragm bearing against said centrally disposedvalve seat; said diaphragm having a central opening normally closed bysaid valve seat, and a tubular bellows communicating between saidopening and said outlet passage; said means including said inlet passagecommunicating with the diaphragm in an annular area outwardly of theseat and an atmospheric passage communicating with the diaphragm in anannular area inwardly of the seat, whereby said valve remains closedunless the inlet pressure is above atmospheric pressure.

2. A valve for controlling fluid flow comprising a housing having inletand outlet passages, a centrally positioned annular valve seat thereindisposed in spaced substantially concentric relation to the inner end ofsaid outlet passage, a valve element in said housing normally closingconnection between said passages, said valve element comprising anannular flexible diaphragm having its inner peripheral edge bearingagainst said annular valve seat, said diaphragm having a tubular bellowsintegral with said inner peripheral edge and providing communicationbetween said inlet passage and said inner end of said outlet passageupon opening the valve, the annular area of said diaphragm outwardly ofsaid valve seat being in direct contact with said inlet flow and theannular area of said diaphragm inwardly of said valve seat being indirect contact with atmospheric pressure whereby the pressure on theinlet side of the diaphragm must be greater than atmospheric pressure toopen the valve to permit fluid to flow therethrough.

3. A valve to control fluid flow comprising a housing having inlet andoutlet passages, a centrally disposed annular valve seat, the inner endof said outlet passage terminating in spaced concentric relation to saidvalve seat, a valve element in said housing normally closing connectionbetween said passages, said valve element comprising an annular flexiblediaphragm having an integral tubular bellows extending from the innerperiphery thereof, the outer peripheral edge of said diaphragm beinghermetically secured to said housing, said inner peripheral edge of saiddiaphragm being in valve seating engagement with said valve seat, andthe outer end of said tubular bellows being hermetically secured to saidinner end of said outlet passage, the inlet side of said diaphragm beingin direct contact with the incoming fluid and the outlet side being incommunication with the atmosphere whereby the pressure on the inlet sideof the diaphragm must be greater than atmospheric pressure to open thevalve to permit fluid to flow therethrongh.

References Cited by the Examiner UNITED STATES PATENTS M. CARY NELSON,Primary Examiner.

MARTIN P. SCHWADRON, Examiner.

S. SCOTT, Assistant Examiner.

1. A VALVE TO CONTROL FLUID FLOW COMPRISING A HOUSING HAVING INLET ANDOUTLET PASSAGES, A CENTRALLY DISPOSED VALVE SEAT, A VALVE ELEMENTNORMALLY CLOSING CONNECTION BETWEEN SAID PASSAGES, MEANS TO PERMITOPENING OF THE VALVE BY PRESSURE IN THE INLET PASSAGE, SAID VALVEELEMENT COMPRISING A DIAPHRAGM BEARING AGAINST SAID CENTRALLY DISPOSEDVALVE SEAT; SAID DIAPHRAGM HAVING A CENTRAL OPENING NORMALLY CLOSED BYSAID VALVE SEAT, AND A TUBULAR BELLOWS COMMUNICATING BETWEEN SAIDOPENING AND SAID OUTLET PASSAGE; SAID MEANS INCLUDING SAID INLET PASSAGECOMMUNICATING WITH THE DIAPHRAGM IN AN ANNULAR AREA OUTWARDLY OF THESEAT AND AN ATMOSPHERIC PASSAGE COMMUNICATING WITH THE DIAPHRAGM IN ANANNULAR AREA INWARDLY OF THE SEAT, WHEREBY SAID VALVE REMAINS CLOSEDUNLESS THE INLET PRESSURE IS ABOVE ATMOSPHERIC PRESSURE.